The contenders: some prototyping engines/toolsets

I will insert the disclaimer that this is by no means an exhaustive list.  This list is more a list of things that I have compiled over the last few years, with my n00bish forays into game development.  That being said, it’s a pretty good list, as I have spent quite a bit of time compiling it (read: it will save you time to read the list).  I won’t bother giving all the details of each, but pretty much everything I will post is somehow free to use to prototype with (unless otherwise specified).

MMORPG

1. Multiverse - if you are the guy in example 1, and are looking for a way to test your MMORPG idea, this is your best bet.  It is a (more or less) complete toolset that can get you going to prototyping every last idea you have.  The community there is large and experienced, so you can get a lot of free support.  This can also take you from prototype to full commercial game.
2. Realm Crafter – this one has been around longer than Multiverse, but also started smaller.  I do not know all the details about it, but it is definitely worth checking out.
3. Crystal Space – although no longer MMO-centric, this is a very powerful engine that has come a long ways in the past few years.  Planeshift, a free MMO, uses it.
4. Project Darkstar – being backed by a large company (Sun) is a good thing.  This is not an entire end-to-end MMORPG solution, but is just the server part of it.  If you already have plans for your client-side engine/toolset, and are looking for a powerful server, this can be it.
5. ICE – this networking layer has been used in more than one MMORPG.  Very powerful and easy to prototype with.  Great documentation.
6. WorldForge – There is a fairly current client for this, and it has been around a while.  They have clients, servers and all that you might need.

3D

1. Ogre3D – Ogre is a very mature and very powerful 3d engine.  It is not a game engine, so you will have to choose sound, networking, physics, input, etc yourself.  This updates all the time and is very active.  Has been used in many commercial games.  You could choose one of many game engines which use it.  StemCell and NeoAxis.
2. Nebula2 – Another open-source 3d engine.  This one has also been used in many commercial games.
3. Torque – Torque is immensely popular and quite widely used.  The licensing is cheap, and they are very active.  They currently have a game engine targeting almost all platforms (PC, Wii, iPhone, XB360, PC).
4. Irrlicht – Yet another open-source 3d engine.  Also has been used in lots of things.  This one has some fairly nice tools.
5. XNA – Microsoft knows what it is doing with version 3.0 of its game framework.  There are large active communities revolving around using XNA.  This is MS’s forte (software development), so don’t let your love for open-source blind you.

Web

1. Flash – very common for prototyping.  Actionscript is a simple language to learn and many games use it.  There are lots of tutorials out there.
2. Silverlight – definitely a contender against flash.  Microsoft is VERY good at making simple languages to learn.  Many open-source zealots oppose it out of principle, but they are missing out on something very powerful.

2D

1. SDL – Very simple and much-used 3d/2d engine.  You should pay homage to SDL.
2. PopCap Games Framework – The framework World of Goo used.  This one is not well-known, but now has some serious clout.
3. AGen – Fairly new, but capable, hardware accelerated 2d game engine.
4. Haaf’s Game Engine – Quick and powerful 2d game engine.
5. LÖVE – Cross-platform and powerful 2d game engine.  Made for rapid prototyping using Lua.
6. Torque – Once again.  They also have a 2d engine for purchase.  You can demo/protoype on an evaluation copy.  Includes an editor.  This one is very popular.
7. XNA – Once again.  Microsoft did a nice job of making this equally powerful in 2d.  Again, there are tons of tutorials and large communities.  I am using this for my current prototype (more details to come in future posts).
8. The Games Factory 2 – Commercial game engine, complete with tools.  They have multiple versions depending on what you need.  Pretty cheap.
9. Novashell – game creation system.  Also fairly popular with tutorials.  Cross-platform and very capable.
10. Cocos2d – Also has an iphone version.  Uses the popular python.  Cross-platform.
11. JGame – A java 2d game engine.
12. EasyWay – Another Java game engine.  Open-source.
13. Andorra 2d – For Delphi and Lazarus.  Robust, mature and award winning.
14. FlatRedBall – This one is C# and XNA based.  I almost went with this over plain XNA for my prototype.

My Opinion

I think you should choose what makes most sense for you and your idea.  If you know exactly the type of game you want, it might make the most sense to find one of these that has a game very similar.  At least you know its possible.  I would also recommend going with the one that has documentation to suit your needs.  You may need to download a lot of them and try them out before you make your choice. My 2d list is so long because that is where I recently did the most research.  I tried 5 or 6 of them out to see if any of them seemed to match up with what I was looking for.

Go with what you know best.  I taught myself some C# for Project Wish and for work.  I ended up using it more at work, but found it very easy.  Because of this, XNA became a very strong contender for me.  Add in the fact that I don’t HATE Microsoft, I own a Zune and an Xbox 360 and it seemed like an easy choice.  That wasn’t enough, however.  My game idea needs physics in order to work.  I had to research physics engines that could add onto whichever game engine I chose.  This helped to narrow down my search, since I didn’t want to spend a ton of time integrating one myself.  I ended up going with Farseer Physics, an open-source one for C#, XNA (PC, Xbox and Zune), and Silverlight.  For me, that’s what ended up clinching it for XNA.

For your game, you might need something different, and will be totally justified with going with something else.  At the end of the day, there are no magic bullets.  Any combination of these tools can work together if you have enough time and dedication to your idea/game.